A generic, universally known exhaust system for an internal combustion system of a motor vehicle has an exhaust catalytic converter and a probe assembly in the area of the exhaust catalytic converter as a component of a lambda control device. By means of the lambda control device the internal combustion engine, as a function of the probe signals detected by the probe assembly, may be switched alternately between a lean-fuel operating range, in which the internal combustion engine is operated with a lean mixture having excess air and thus excess oxygen and a rich-fuel operating range, in which the internal combustion engine is operated with an air deficiency and thus oxygen deficiency.
Specifically, a lambda pilot probe is mounted upstream from the exhaust catalytic converter and a lambda control probe downstream from the catalytic converter. The lambda pilot probe is a so-called constant lambda probe, which is used for lambda control upstream from the catalytic converter. It is capable of detecting a relatively wide lambda signal in the range of about 0.7 to about 2. The object of using the probe is to measure deviation of the lambda generated by the engine from the assigned lambda. The lambda control probe, which is a binary lambda probe, generally can detect the passage only when lambda=1, but with very high accuracy. Such high accuracy is required for equalization to precisely lambda=1. Appropriate wiring is required for both sensors; the required structural space must also be present for both sensors.